There are conflicting reports about the nationalities of those kidnapped. Gunmen have abducted seven foreign construction workers at a site in Bauchi state, after killing the security guard, police say.
The attack occurred at the Lebanese-owned firm, Setraco, on Saturday. The attackers also targeted a prison and a police station Jama'are in Bauchi.
At least one Briton was amongst those kidnapped, British media say. Some reports say some of those kidnapped are Nigerians.
The State police commissioner, Mohammed Ladan, who confirmed the incident, did not release the nationalities of those kidnapped, News Agency of Nigeria reports. Unconfirmed reports say Greek and Italian nationals may have also been involved.
Mr. Ladan said the gunmen had also attempted to attack the Ganjuwa Police station, but were repelled by his men.
No group has claimed responsibility for the attack.
The construction firm is handling the road project from Shuwarin in Jigawa, to Azare in Bauchi State.